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Search Results: 1 - 10 of 26809 matches for " YI Hecheng "
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Characterizing and Modeling the Structure of Competition Networks  [PDF]
Bo Yang, Hecheng Wang
Journal of Service Science and Management (JSSM) , 2011, DOI: 10.4236/jssm.2011.41002
Abstract: Not similar with the current interest on collaboration networks research, the focus in this paper is competition networks. The topology of a firm competition network has been investigated empirically and theoretically. We have found that four fundamental characteristics emerge simultaneously in the competition network, including hierarchical modularity, positive degree correlation, power-law degree distribution and self-similarity. The theoretical model we proposed can predict these structural patterns successfully. The obtained results are significant for further network analysis of the omnipresent competitive phenomena.
An Evolutionary Algorithm Based on a New Decomposition Scheme for Nonlinear Bilevel Programming Problems  [PDF]
Hecheng LI, Yuping WANG
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2010, DOI: 10.4236/ijcns.2010.31013
Abstract: In this paper, we focus on a class of nonlinear bilevel programming problems where the follower’s objective is a function of the linear expression of all variables, and the follower’s constraint functions are convex with respect to the follower’s variables. First, based on the features of the follower’s problem, we give a new decomposition scheme by which the follower’s optimal solution can be obtained easily. Then, to solve efficiently this class of problems by using evolutionary algorithm, novel evolutionary operators are designed by considering the best individuals and the diversity of individuals in the populations. Finally, based on these techniques, a new evolutionary algorithm is proposed. The numerical results on 20 test problems illustrate that the proposed algorithm is efficient and stable.
An Evolutionary Algorithm for Solving Bilevel Programming Problems Using Duality Conditions
Hecheng Li,Lei Fang
Mathematical Problems in Engineering , 2012, DOI: 10.1155/2012/471952
Abstract: Bilevel programming is characterized by two optimization problems located at different levels, in which the constraint region of the upper level problem is implicitly determined by the lower level problem. This paper is focused on a class of bilevel programming with a linear lower level problem and presents a new algorithm for solving this kind of problems by combining an evolutionary algorithm with the duality principle. First, by using the prime-dual conditions of the lower level problem, the original problem is transformed into a single-level nonlinear programming problem. In addition, for the dual problem of the lower level, the feasible bases are taken as individuals in population. For each individual, the values of dual variables can be obtained by taking the dual problem into account, thus simplifying the single-level problem. Finally, the simplified problem is solved, and the objective value is taken as the fitness of the individual. Besides, when nonconvex functions are involved in the upper level, a coevolutionary scheme is incorporated to obtain global optima. In the computational experiment, 10 problems, smaller or larger-scale, are solved, and the results show that the proposed algorithm is efficient and robust.
Is Uniportal More Advantageous Than Three Portal in Alleviating Acute and Chronic Pain after Lobectomy?
Hecheng LI, Yajie ZHANG
- , 2018, DOI: : 10.3779/j.issn.1009-3419.2018.04.10
Abstract:
Heavy metal pollution in soils and characteristics of heavy metal accumulation of dominant plants in antimony mining area
锑矿区土壤重金属污染及优势植物对重金属的富集特征

Ku Wenzhen,Zhao Yunlin,Lei Cunxi,Dong Meng,Dai Meibin,Yi Hecheng,
库文珍
,赵运林,雷存喜,董萌,戴枚斌,易合成

环境工程学报 , 2012,
Abstract: 通过野外调查采样,分析了冷水江锑矿区4个采样点土壤和优势植物中重金属含量,以及矿区生长的5种优势植物对Sb、As、Cd、Pb、Cu和Zn的的吸收与富集能力及其富集特性。结果表明,矿区土壤中6种重金属元素的平均含量均超出湖南省土壤背景值和全国土壤背景值,土壤受Sb污染最严重,其次是Cd、As的污染。5种优势植物淡竹叶、苎麻、芒草、狗尾草和白背叶体内Sb、As的含量都超过正常范围,具有修复矿区土壤Sb、As污染的潜力。其中苎麻对Sb的富集系数和转运系数均大于1,满足Sb超富集植物的基本特征,可作为生态恢复的先锋植物;芒草对Cd的富集系数和转运系数都大于1,对重金属有较强的耐性,作为重金属污染的修复植物具有较好的应用前景。
Growth responses and phytoremediation potential of Artemisia selengensis to Cd stress
蒌蒿(Artemisia selengensis)对土壤中镉的胁迫反应及修复潜力研究

DONG Meng,ZHAO Yunlin,LEI Cunxi,DAI Meibin,YI Hecheng,KU Wenzhen,
董萌
,赵运林,雷存喜,戴枚斌,易合成,库文珍

环境科学学报 , 2012,
Abstract: Artemisia selengensis grown in Dongting Lake wetland was recently found as a plant with good capacity in enriching Cd. A pot experiment was conducted to study the biological traits and the Cd accumulation characteristics of Artemisia selengensis to Cd stress during its growth period. The final results showed that the leaves were injured apparently in response to significant decrease of above-ground biomass when Cd concentrations in soil were higher than 40 mg·kg-1. Artemisia selengensis could complete its life cycle at a high Cd concentration (100 mg·kg-1) and showed strong resistence to soil Cd. The bioavailable Cd accounted for 15.3%~37.1% of total soil Cd. There were no significant differences of Cd concentrations in the plants during their different growth phases, but a lower Cd accumulation was observed in stems and leaves at the seedling stage than the other stages because of low biomass. During the adult stage of Artemisia selengensis, Cd accumulation was up to 492~588 mg·kg-1 under the Cd treatment of 40~60 mg·kg-1. These data suggested that Artemisia selengensis was an outstanding species that could be selected as a potential candidate to repair Cd pollution from lake soil.
Arsenic trioxide exerts synergistic effects with cisplatin on non-small cell lung cancer cells via apoptosis induction
Hecheng Li, XiaoLi Zhu, Yawei Zhang, Jiaqing Xiang, Haiquan Chen
Journal of Experimental & Clinical Cancer Research , 2009, DOI: 10.1186/1756-9966-28-110
Abstract: A549 and H460 human lung cancer cells were treated with As2O3 and/or DDP. Cell growth curves, cell proliferation, cell cycle, and apoptosis of human cancer cell lines were determined by the 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) method, clonogenic assay, and flow cytometry (FCM). Apoptosis was further assessed by TUNEL staining. Cell cycle and apoptosis related protein p21, cyclin D1, Bcl-2, bax, clusterin, and caspase-3 were detected by western blot.MTT and clonogenic assay showed As2O3 within 10-2 μM to 10 μM exerted inhibition on the proliferation of NSCLC cells, and 2.5 μM As2O3 exerted synergistic inhibition on proliferation with 3 μg/ml DDP. The combination indices (CI) for A549 and H460 were 0.5 and 0.6, respectively, as confirmed by the synergism of As2O3 with DDP. FCM showed As2O3 did not affect the cell cycle. The G0/G1 fraction ranged from 57% to 62% for controlled A549 cells and cells treated with As2O3 and/or DDP. The G0/G1 fraction ranged from 37% to 42% for controlled H460 cells and cells treated with As2O3 and/or DDP. FCM and TUNEL staining illustrated that the combination of As2O3 and DDP provoked synergistic effects on apoptosis induction based on the analysis of the apoptosis index. Western blotting revealed that the expression of cell cycle related protein p21 and cyclin D1 were not affected by the treatments, whereas apoptosis related protein bax, Bcl-2, and clusterin were significantly regulated by As2O3 and/or DDP treatments compared with controls. The expression of caspase-3 in cells treated with the combination of As2O3 and DDP did not differ from that in cells treated with a single agent.As2O3 exerted synergistic effects with DDP on NSCLC cells, and the synergistic effects were partly due to the induction of caspase-independent apoptosis.Lung cancer is the number one cause of cancer mortality in both males and females worldwide [1]. Despite multidisciplinary treatment, lung cancer is still a highly lethal dise
Chinese herbal extract reduces Amyloid-β induced neurotoxicity through inhibiting NF-κB signaling pathway in neuronal cells
Wu Xuehua,Yu Yan,Zhou Liang,Wang Hecheng
Molecular Neurodegeneration , 2012, DOI: 10.1186/1750-1326-7-s1-s28
Abstract:
Grid Dependent Tasks Security Scheduling Model and DPSO Algorithm
Hai Zhu,Yuping Wang,Zhanxin Ma,Hecheng Li
Journal of Networks , 2011, DOI: 10.4304/jnw.6.6.850-857
Abstract: Due to the security threat to task scheduling problems in the grid environment, by considering both the inherent security and behavior safety of grid resource nodes, security benefit functions and credibility assessment strategies of grid resource nodes are constructed respectively. At the same time, the corresponding membership function is established in order to establish the membership between task security requirements and resource security attributes. Based on these, a new grid dependent tasks security scheduling model is set up. In order to solve this model, the particle evolution equation is re-designed by combining the specific characteristics of the dependent task scheduling problem. Meanwhile, in order to prevent the algorithm falling into local optimum, a uniform speed of disturbance is adopted and a new discrete Particle Swarm Optimization algorithm is proposed. Simulation results show that this algorithm has better scheduling length and higher safety performance than the genetic algorithm.
The True Value of a Sample Composition Is There  [PDF]
Hong Yi, Wei Yi
American Journal of Analytical Chemistry (AJAC) , 2015, DOI: 10.4236/ajac.2015.64027
Abstract: The core objective of a chemical composition measurement is to determine its true value. However, when measuring the composition of a macroscopic sample with a large number of atoms or molecules, realizing the true value of the measurand at both the macroscopic and microscopic levels remains an unsolved theoretical problem. We find that the true value of a sample composition exists in any subsample of a homogeneous molecular population of the sample. Here, we propose the Central Law of Measurement of the Amount of Substance: “The homogeneity of a sample molecular population represents the measurement accuracy of the sample composition in an analytical procedure”. The Central Law is based on a homogeneous molecular population axiom in which the molecular composition of a sample is identical for any homogeneous subsample. Furthermore, we point out that, at the microscopic scale, Avogadro’s law does not hold true.
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